The present invention relates to a paper supplying device used in an image forming apparatus such as an electrostatic copying machine or a printer, in particular to a paper supplying device in which a paper supplying cassette is adapted to be inserted into and extracted from a paper supplying portion in the direction of an axis of rotation of a paper supplying roller.
With such paper supplying device, a disadvantage occurs in that, for example, when the paper supplying cassette is charged in the direction of the axis of rotation of the paper supplying roller, papers housed in the paper supplying cassette in layers are engaged with an end face portion of the paper supplying roller, and thereby can become damaged or shifted sideways.
A paper supplying device having a construction shown in FIG. 13 has been employed by the present applicant (MITA INDUSTRIAL CO. LTD) as a paper supplying device capable of solving such disadvantage (Japanese Patent Application No. Hei 1-183476, U.S. patent application Ser. No. 07/552,691).
In such paper supplying device, a paper supplying roller 62 of a paper supplying portion 61 is provided so as to be removable in the direction of an axis of rotation, a paper supplying cassette 63 being provided so as to be inserted into and extracted from paper supplying portion 61 in the direction of the axis of rotation of paper supplying roller 62. Paper supplying cassette 63, when inserted into the paper supplying portion 61, is lifted by pressing means 67 composed of a cam roller 66 and a cam member 65 provided on the paper supplying cassette 63 and a guide member 64, respectively, to press an upper surface of papers (a) housed in layers in the paper supplying cassette 63 against the paper supplying roller 62.
In addition, a member to be pressed 68 receives a pressing force from the paper supplying cassette 63 before the upper surface of papers (a) is pressed against the paper supplying roller 62. Member 68 is mounted on a member 69 that is movable in a direction of movement of the paper supplying roller 62. Roller 62 is connected to movable member 69 so as to be rotatable relative thereto. Thus, member 68 may move in the cassette inserting direction integrally with the paper supplying roller 62 by member 68 being pressed by the paper supplying cassette 63 before the upper surface of the papers (a) is pressed against the paper supplying roller 62. The member 68 and the paper supplying roller 62 are returned to an initial position by means of returning means 71 connected between the movable member 69 and a fixed member. With such construction, the paper supplying roller 62 moves in the cassette inserting direction integrally with the paper supplying cassette 63 from a midway of the insertion of the paper supplying cassette 63 into the paper supplying portion 61, thus gradually lifting the paper supplying cassette 63 in an inclined manner by a guiding action of pressing means 67. Thus, the upper surface of the papers (a) within the paper supplying cassette 63 is pressed against the paper supplying roller 62. Accordingly, the papers can be prevented from being damaged and shifted sideways in spite of the fact that cassette 63 is possibly inserted and extracted in the direction of the axis of rotation of the paper supplying roller 62.
However, in the above described paper supplying device, the member 68 and a plate member 72 connected with the movable member 69 at opposite ends thereof in the cassette inserting direction are provided with respective notched engaging portions 74, with which a roller shaft 73 of the paper supplying roller 62 is engaged. Two circular grooves 75 are formed in roller shaft 73 at positions corresponding to outer side surfaces of respective notched engaging portions 74. Each respective circular groove 74 is provided with a seat 76 mounted therein. The member 68 being engaged with the respective seat 76 thereof on the downstream side thereof in the cassette inserting direction. Plate member 72 is engaged with the respective direction. Thereby, the member 68 is connected with the roller shaft 73. However, this construction has the disadvantage that assembly efficiency is not satisfactory. Furthermore, two circular grooves 75 must be formed in the roller shaft 73 such that manufacturing costs of the roller shaft 73 thereby are increased.